Swordsmanship is like asking questions, & if 相手 answers wrong, they'll be cut. However, 自分 takes this a bit further by asking questions on a conceptual level, his swordsmanship cutting through 相手's soul w/ his own Enlightenment.
[What Is Death?]: In the final clash, 自分 brings forth his ultimate enlightenment, that "Death is The Dissolution of Identity, Becoming Part of The Universe Once More"